Guarding the gateway to histidine biosynthesis in plants: Medicago truncatula ATP-phosphoribosyltransferase in relaxed and tense states

2018 ◽  
Vol 475 (16) ◽  
pp. 2681-2697
Author(s):  
Milosz Ruszkowski
Keyword(s):  
Medicago Truncatula ◽  
Feedback Inhibition ◽  
Histidine Biosynthesis ◽  
Peptide Backbone ◽  
Model Legume ◽  
Regulatory Domains ◽  
Legume Plant ◽  
Eukaryotic Organism ◽  
Α Helix ◽  
T State

In the first committed step of histidine biosynthesis, adenosine 5′-triphosphate (ATP) and 5-phosphoribosyl-α1-pyrophosphate (PRPP), in the presence of ATP phosphoribosyltransferase (ATP-PRT, EC 2.4.2.17), yield phosphoribosyl-ATP. ATP-PRTs are subject to feedback inhibition by histidine that allosterically binds between the regulatory domains. Histidine biosynthetic pathways of bacteria, lower eukaryotes, and plants are considered promising targets for the design of antibiotics, antifungal agents, and herbicides because higher organisms are histidine heterotrophs. Plant ATP-PRTs are similar to one of the two types of their bacterial counterparts, the long-type ATP-PRTs. A biochemical and structural study of ATP-PRT from the model legume plant, Medicago truncatula (MedtrATP-PRT1) is reported herein. Two crystal structures, presenting homohexameric MedtrATP-PRT1 in its relaxed (R-) and histidine-bound, tense (T-) states allowed to observe key features of the enzyme and provided the first structural insights into an ATP-PRT from a eukaryotic organism. In particular, they show pronounced conformational reorganizations during R-state to T-state transition that involves substantial movements of domains. This rearrangement requires a trans- to cis- switch of a peptide backbone within the hinge region of MedtrATP-PRT1. A C-terminal α-helix, absent in bacteria, reinforces the hinge that is constituted by two peptide strands. As a result, conformations of the R- and T-states are significantly different from the corresponding states of prokaryotic enzymes with known 3-D structures. Finally, adenosine 5′-monophosphate (AMP) bound at the active site is consistent with a competitive (and synergistic with histidine) nature of AMP inhibition.

The Impact of Simulated Microgravity on the Growth of Different Genotypes of the Model Legume Plant Medicago truncatula

2018 ◽  
Vol 30 (4) ◽  
pp. 491-502 ◽  
Author(s):  
Gemma Lionheart ◽  
Joshua P. Vandenbrink ◽  
Jason D. Hoeksema ◽  
John Z. Kiss
Keyword(s):  
Medicago Truncatula ◽  
Simulated Microgravity ◽  
Model Legume ◽  
Legume Plant ◽  
The Impact

A study on the susceptibility of the model legume plant Medicago truncatula to the soil-borne pathogen Fusarium oxysporum

2009 ◽  
Vol 126 (4) ◽  
pp. 517-530 ◽  
Author(s):  
Montserrat Ramírez-Suero ◽  
Anas Khanshour ◽  
Yves Martinez ◽  
Martina Rickauer
Keyword(s):  
Fusarium Oxysporum ◽  
Medicago Truncatula ◽  
Model Legume ◽  
Legume Plant

scholarly journals Characterization of the Interaction Between the Bacterial Wilt Pathogen Ralstonia solanacearum and the Model Legume Plant Medicago truncatula

2007 ◽  
Vol 20 (2) ◽  
pp. 159-167 ◽  
Author(s):  
Fabienne Vailleau ◽  
Elodie Sartorel ◽  
Marie-Françoise Jardinaud ◽  
Fabien Chardon ◽  
Stéphane Genin ◽  
...  
Keyword(s):  
Plant Species ◽  
Medicago Truncatula ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Recombinant Inbred Lines ◽  
Model Legume ◽  
Legume Plant ◽  
Hrp Genes

The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt and attacks more than 200 plant species, including some legumes and the model legume plant Medicago truncatula. We have demonstrated that M. truncatula accessions Jemalong A17 and F83005.5 are susceptible to R. solanacearum and, by screening 28 R. solana-cearum strains on the two M. truncatula lines, differential interactions were identified. R. solanacearum GMI1000 infected Jemalong A17 line, and disease symptoms were dependent upon functional hrp genes. An in vitro root inoculation method was employed to demonstrate that R. solanacearum colonized M. truncatula via the xylem and intercellular spaces. R. solanacearum multiplication was restricted by a factor greater than 1 × 105 in the resistant line F83005.5 compared with susceptible Jemalong A17. Genetic analysis of recombinant inbred lines from a cross between Jemalong A17 and F83005.5 revealed the presence of major quantitative trait loci for bacterial wilt resistance located on chromosome 5. The results indicate that the root pathosystem for M. truncatula will provide useful traits for molecular analyses of disease and resistance in this model plant species.

scholarly journals Calmodulin-Like (CML) Gene Family in Medicago truncatula: Genome-Wide Identification, Characterization and Expression Analysis

2020 ◽  
Vol 21 (19) ◽  
pp. 7142
Author(s):  
Qiguo Sun ◽  
Shuhan Yu ◽  
Zhenfei Guo
Keyword(s):  
Gene Family ◽  
Medicago Truncatula ◽  
Expression Analysis ◽  
Model Legume ◽  
Cis Acting ◽  
Biotic Stresses ◽  
Genome Wide ◽  
Legume Plant ◽  
Ef Hand ◽  
Blast Database

Calcium is an important second messenger in mediating adaptation responses of plants to abiotic and biotic stresses. Calmodulin-like (CML) protein is an important calcium-signaling protein that can sense and decode Ca2+ signal in plants. Medicago truncatula is a model legume plant; however, investigations of MtCML proteins are limited. Using genome analysis and BLAST database searches, fifty MtCML proteins that possess EF-hand motifs were identified. Phylogenetic analysis showed that CML homologs between M. truncatula, Arabidopsis thaliana and Oryza sativa shared close relationships. Gene structure analysis revealed that these MtCML genes contained one to four conserved EF-hand motifs. All MtCMLs are localized to eight chromosomes and underwent gene duplication. In addition, MtCML genes were differentially expressed in different tissues of M. truncatula. Cis-acting elements in promoter region and expression analysis revealed the potential response of MtCML protein to abiotic stress and hormones. The results provide a basis of further functional research on the MtCML gene family and facilitate their potential use for applications in the genetic improvement on M. truncatula in drought, cold and salt stress environments.

scholarly journals Assessment of the function and expression pattern of auxin response factor B3 in the model legume plant Medicago truncatula

2017 ◽  
Vol 41 ◽  
pp. 66-76 ◽  
Author(s):  
Miglena REVALSKA ◽  
Valya VASSILEVA ◽  
Grigor ZEHIROV ◽  
Sofie GOORMACHTIG ◽  
Anelia IANTCHEVA
Keyword(s):  
Expression Pattern ◽  
Medicago Truncatula ◽  
Auxin Response Factor ◽  
Response Factor ◽  
Auxin Response ◽  
Model Legume ◽  
Legume Plant

scholarly journals Crystal structure of thermospermine synthase from Medicago truncatula and substrate discriminatory features of plant aminopropyltransferases

2018 ◽  
Vol 475 (4) ◽  
pp. 787-802 ◽  
Author(s):  
Bartosz Sekula ◽  
Zbigniew Dauter
Keyword(s):  
Crystal Structures ◽  
Medicago Truncatula ◽  
Higher Plants ◽  
Structural Features ◽  
Scattering Data ◽  
Model Legume ◽  
Spermine Synthase ◽  
X Ray Scattering ◽  
Legume Plant ◽  
Aminopropyl Group

Polyamines are linear polycationic compounds that play a crucial role in the growth and development of higher plants. One triamine (spermidine, SPD) and two tetraamine isomers (spermine, SPM, and thermospermine, TSPM) are obtained by the transfer of the aminopropyl group from decarboxylated S-adenosylmethionine to putrescine and SPD. These reactions are catalyzed by the specialized aminopropyltransferases. In that respect, plants are unique eukaryotes that have independently evolved two enzymes, thermospermine synthase (TSPS), encoded by the gene ACAULIS5, and spermine synthase, which produce TSPM and SPM, respectively. In this work, we structurally characterize the ACAULIS5 gene product, TSPS, from the model legume plant Medicago truncatula (Mt). Six crystal structures of MtTSPS — one without ligands and five in complexes with either reaction substrate (SPD), reaction product (TSPM), or one of three cofactor analogs (5′-methylthioadenosine, S-adenosylthiopropylamine, and adenosine) — give detailed insights into the biosynthesis of TSPM. Combined with small-angle X-ray scattering data, the crystal structures show that MtTSPS is a symmetric homotetramer with an interdomain eight-stranded β-barrel. Such an assembly and the presence of a hinge-like feature between N-terminal and C-terminal domains give the protein additional flexibility which potentially improves loading substrates and discarding products after the catalytic event. We also discuss the sequence and structural features around the active site of the plant aminopropyltransferases that distinguish them from each other and determine their characteristic substrate discrimination.

scholarly journals Full-Size ABC Transporters from the ABCG Subfamily in Medicago truncatula

2009 ◽  
Vol 22 (8) ◽  
pp. 921-931 ◽  
Author(s):  
Michal Jasinski ◽  
Joanna Banasiak ◽  
Marcin Radom ◽  
Anna Kalitkiewicz ◽  
Marek Figlerowicz
Keyword(s):  
Medicago Truncatula ◽  
Abc Transporters ◽  
Root Nodules ◽  
Lotus Japonicus ◽  
Messenger Rnas ◽  
Model Legume ◽  
Full Size ◽  
Signaling Systems ◽  
Legume Plant ◽  
Genes Encoding

Full-size ATP-binding cassette (ABC) transporters belonging to the ABCG subfamily are unique for plants and fungi. There is growing evidence that certain of these proteins play a role in plant defense or signaling systems. As yet, a complete set of full-size ABCG protein genes has been inventoried and classified in only two plants: Arabidopsis thaliana and Oryza sativa. Recently, a domain-based clustering analysis has predicted the presence of at least 12 genes encoding such proteins in the Lotus japonicus genome. Here, we identify and classify 19 genes coding full-size ABCG proteins in Medicago truncatula, a model legume plant. We have found that the majority of these genes are expressed in roots and flowers whereas only a few are expressed in leaves. Expression of several has been induced upon pathogenic infection in both roots and leaves. ABCG messenger RNAs have been detected in root nodules forming during symbiosis of legume plants and nitrogen-fixing bacteria. The data presented provide a scaffold for further studies of the physiological function of Medicago ABCG transporters and their possible role in modulating plant–microorganism interactions.

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